## What is a Resistor

A Resistor is a passive electronic component having two terminals, that limits the flow of electrons through a circuit. Passive components are the components that can only consume power (they cannot generate power).

## Uses of Resistors

The main use of resistors is to reduce the flow of current in a circuit, but it is not limited to this only. Resistors find applications in various fields like-
*Resistors can be used to divide voltages (as voltage divider)
*Terminating transmission lines
*To bias active elements
*Timing and frequency applications
*In heating applications etc.

Resistors can broadly be categorized into two types-
*Fixed Resistors
*Variable Resistors

#### Fixed resistors

As clear by its name, fixed resistors cannot change it's value.
The fixed resistors can again be classified into following three types-
*Carbon composition resistors
*Metalized resistors
*Wire wound resistors

#### Variable resistors

The resistance of variable resistors can be changed continually or can be set to a certain value as per the requirement.
On the basis of this the variable resistors can again be of two types-
*The variable resistors that can change its value continually like that used in volume control applications and
*The variable resistors that can be set to a fixed value as desired like in case of potentiometers (adjustable resistor).

## Working Principle of resistor

#### Ohm's Law

For an ideal resistor the Ohm's law is given as -
According to Ohm's law the voltage (V) across a resistor is directly proportional to the current (I) flowing through it. Here the constant of proportionality is the resistance (R).
This relationship between voltage and current is given as-
V=IR

## Unit of Resistance (R) and Conductance (G)

Unit of electrical resistance is Ohm (Ω) . Ohm is the SI unit of resistance. Other unit of resistance can be obtained from the Ohm's law.
By Ohm's law-
R=V/I
Therefore the unit of resistance is- Volt per Ampere or V/A.
Conductance (G) is opposite to the resistance. Conductance can be defined as the ease with which the current flows through a substance. Formerly the unit of conductance was mho (℧)(opposite of Ohm, the unit of resistance). The standard unit of conductance is siemens (S).

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AMPLITUDE MODULATION (TIME DOMAIN EQUATIONS AND WAVEFORMS)

STEP INDEX OPTICAL FIBER (MULTIMODE AND SINGLE MODE STEP INDEX FIBERS)

PULSE MODULATION TECHNIQUES (PAM, PWM, PPM, PCM)

OPTICAL FIBER: STRUCTURE AND WORKING PRINCIPLE

PULSE AMPLITUDE MODULATION (PAM)

COMPARISON OF PAM, PWM, PPM MODULATION TECHNIQUES

PULSE WIDTH MODULATION (PWM)

CONTINUOUS TIME AND DISCRETE TIME SIGNALS (C.T. AND D.T. SIGNALS)

NEED AND BENEFITS OF MODULATION

PULSE POSITION MODULATION (PPM)

OPTICAL FIBERS IN COMMUNICATION: COVERS ALL IMPORTANT POINTS

OPTICAL FIBER SOURCES (DESIRABLE PROPERTIES)

SAMPLING THEOREM AND RECONSTRUCTION (SAMPLING AND QUANTIZATION)

SUPERPOSITION THEOREM (BASICS, SOLVED PROBLEMS, APPLICATIONS AND LIMITATIONS)

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Conventional AM Vs DSB-SC Vs SSB-SC Vs VSB (Comparison of AM Systems)

What are Microwaves and their Applications (Uses) in various fields

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